# Highlight changes in a specific entry of a reference list created with biblatex

I would like to highlight changes in a specific entry (or even a part of the entry) of a reference list created with biblatex, e.g., by changing the font color to red. (Unfortunately such a feature is not available in todonotes.)

Apart from the conversation here, I couldn't find anything helpful. Two examples are given there, but I was not able to run them correctly.

Example 1

%For example, if you want to print the title of recent entries in red,
%you'd modify the "title" format:

\documentclass{article}
\usepackage{biblatex}
\usepackage{color}
\bibliography{biblatex-examples}
\DeclareFieldFormat*{title}{%
\usebibmacro{color_recent}{\mkbibemph{#1}}}
\newbibmacro{color_recent}[1]{%
\iffieldint{year}
{\ifnumgreater{\thefield{year}}{1999}
{\textcolor{red}{#1}}
{#1}}
{#1}}
\begin{document}
\nocite{*}
\printbibliography
\end{document}


Example 2

%If you want the complete entry in red, it's easier to use a hook like
%\AtEveryBibitem:

\documentclass{article}
\usepackage{biblatex}
\usepackage{color}
\bibliography{biblatex-examples}
\AtEveryBibitem{%
\iffieldint{year}
{\ifnumgreater{\thefield{year}}{1999}
{\color{red}}
{}}
{}}
\begin{document}
\nocite{*}
\printbibliography
\end{document}


My error

For both examples I get:

! Undefined control sequence.
<argument> Przepi\x
{fffd}\x {fffd}rka
l.19 \end
{document}
?

-
Both examples works well. I think you should update your system. – Marco Daniel Apr 18 '12 at 17:09
Judging from your error message, it seems to be an encoding problem. – domwass Apr 18 '12 at 18:06
Thanks for your help! I'm working with pdfTeX 3.1415926-2.3-1.40.12 (TeX Live 2011) on Debian Squeeze and I updates all packages. The input file is encoded in UTF-8, I use nothing else. Am I missing something? – deboerk Apr 19 '12 at 10:22
@deboerk: Use \usepackage[utf8]{inputenc} and \usepackage[T1]{fontenc} – Marco Daniel Apr 20 '12 at 18:47
Now it's working. Thanks very much! How can I mark this question as solved? – deboerk Apr 22 '12 at 18:58

The error occurs by an encoding problem. To avoid this you can load the package inputenc with your used encoding. Normally the encoding is utf8.
\usepackage[utf8]{inputenc}